Self-baking electrodes are also called Soderberg electrode. Its development history can be traced back to 1909. At that time, Norwegian engineer Soderberg, did such an experiment. Heat and radiant heat from the surface of the electric furnace were used for firing, and as a result, self-baking electrodes were successfully obtained.
The self-baking electrode is composed of the electrode cylinder and the electrode paste inside. The electrode cylinder is rolled and welded by steel plate, with fins and iron bars inside, which can transmit current and increase the click strength. The vertical ribs of the electrode cylinder and the openings in the cross section solve the problem of the detachment of the electrode paste from the electrode cylinder, making the electrode copper and the electrode paste more firmly bonded to facilitate current conduction. The electrode cylinder is installed in the electrode holder and extends into the reaction zone of the furnace through the electrode clamping device. The electrodes are constantly consumed while working in the furnace, so it is necessary to constantly lower the electrodes, fill the electrode paste and weld new electrode cylinders.
The electrode paste is put into the electrode cylinder and moves downward with the electrode cylinder at the same time, continuously consumed and replenished. During this process, the electrode paste undergoes three phase changes, namely solid-liquid-solid. In the greenhouse (25°C), the electrode paste is solid. When the temperature rises from 25°C to 120-250°C, the electrode paste melts into a thin paste, and the resistance increases at the same time. When the temperature rises to 300-750°C, the electrode paste The volatile substances in the liquid volatilize and gradually become viscous, forming a coke-like substance, and the resistance gradually decreases. When the temperature reaches 800-900°C, the electrode paste is basically sintered into an electrode. During this conversion process, the electrode paste is roasted into an electrode. Its strength Gradually increased, while the resistivity gradually decreased to below 100μΩ·m.
After high-temperature roasting above 1000°C, the electrode paste is completely carbonized to form a carbon electrode, which can conduct electricity and convert energy in the molten pool of the submerged electric furnace. Because the electrode cylinder is welded without power failure, the electrode paste is also without power failure In case of addition, the electrode is continuously consumed, and the electrode paste is continuously roasted to form an electrode, so it is called a continuous automatic roasting electrode, referred to as a self-baking electrode. Self-baking electrodes are widely used in calcium carbide furnaces and ferroalloy furnaces. This electrode is characterized by a diameter that can be increased to 2m, which creates favorable conditions for submerged arc furnaces with large load capacity, and is low in price and easy to operate.
